JOURNAL OF MICROSCOPICAL SCIENCE. 
EXPLANATION OF PLATES I & II, 
Illustrating Mr. Francis H. Welch’s Observations on the 
Anatomy of Tenia mediocanellata. 
PLATE I. 
Fic. 1 x 10 diameters. Transverse section of an adult segment carried 
through the genital pit. 
a, body structure; 4, visceral space; c, longitudinal water-vascular 
canals; d, genital pit; e, penis slightly protruded; f, vagina; g,_ 
seminal duct; 4, uterus; 7, seminal glands; 4, ovarian glands. From 
the position of the genital ducts to the water-vascular system (/) a 
dorsal and (m) ventral surface of the segment can be formed. 
Fic. 2 x 10 diameters. Longitudinal section of one half of an adult 
segment. (For natural reading of figs. 2 and 2 turn the plate sideways 
with fig. 2 to left hand.) 
a, body structure; 6, visceral substance ; c, longitudinal water-vascular 
canal; d, bulbous expansion of the canal at its junction with the 
transverse branch,e ; f, genital pit; g, penis; 4, vagina; 7, junction of 
vagina with uterus; k, uterus; /, fibrous sheath enclosing seminal 
duct and glands ; m, ovarian ducts; ~, ovarian glands. 
Fic. 3 x 10 diameters. Vertical section of an adult segment and portions 
of the contiguous ones, carried through the centre of the zooid. 
a, body structure ; 4, visceral space; ¢, inflexion of the body structure at 
the junction of segments, there the calcareous particles are in a mi- 
nority; d, lumen of the transverse water-vascular canal; e, fibrous 
diaphragm beneath it ; 7 junction of vagina with uterus towards a flat 
surface of the zooid, that surface ventral; g, projections of the uterine 
canal encroached on by the knife in section ; 4, ovarian glands. 
Fic. 4 x 140 diameters. Transverse section of the skin and body 
structure. 
a, epidermis; 4, corium; ¢c, granular layer; d, circular muscular bands ; 
e, portion of the circular coat not encroached on by the transverse 
bands (/), which have between them calcareous particles. 
Fic. 5 X 140 diameters. Longitudinal section of the body structure. 
a, bands of longitudinal muscular fibre; 4, parenchyma with calcareous 
particles. 
Fic. 6 x 500 diameters. Inorganic accretions, “ calcareous corpuscles.” 
a, concentric laminated nodules of carbonate of lime; 6, homogeneous 
nodules, some lime carbonate, some fat; ¢, irregular crystals in masses, 
phosphatic. 
PLATE II. 
Fic. 7 X 140 diameters. Longitudinal section of penis, the tip and bulb 
are shown, the intermediate part left out, as requiring too much space 
for delineation. 
a, skin of genital pit and muscular layers of body: 4, inflexion of fibres 
which assist in forming a sheath; c, depth of preputial inflexion; d, 
external cylinder inflected at the tip (e), and forming the bulb (/); 
g, internal cylinder, lined by ciliated epithelium ; the canal is purposely 
dilated in the sketch, to render the ciliz apparent ; 4, internal bulb; 
2, convoluted tube; 4%, longitudinal muscular bands between the 
cylinders ; /, seminal duct; m, vaginal aperture; 2, muscular part of 
vagina lined by ciliz. Similar remarks apply to this canal as to that of 
the penis. 
